Rubmstein created the software's specifications and commissioned programmer Rob Barnaby to follow through.
Since its introduction in 1979 WordStar has been enjoyed by over a million fans, though not all have been paying customers.

" MONITOR") operating system version 1.2. IMSAI's Chief Programmer Rob Barnaby came on board at IMS Associates in late 1976 and worked closely with Gary for about 4 months, writing the I/O routines and embellishing some of Gary's original PL-1 source code.

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Barnaby quickly absorbed the full extent of knowledge and performance of the development system and was soon clamoring for more computing and development power.

{34} Rob Barnaby, a programmer, claims that he wrote most of the code for Wordstar while working for another company, IMSAI. [31] Barnaby's program was a masterful tour de force, packing a full blown word processor into a tiny 64k CP/M machine.
According to John Judis, "when Barnaby, repelled by Micropro International's corporate culture, quit, the firm's team of programmers were unable to master and improve Barnaby's code.